This invention relates generally to a system for reducing the temperature of components in a computer system. More particularly, the invention pertains to a refrigeration system having multiple evaporators connected in parallel for receiving individually metered amounts of refrigerant to thus reduce temperature variation among components in a multi-component system.
The components (e.g., processors, micro-controllers, high speed video cards, disk drives, semi-conductor devices, etc.) of a computer system are generally known to generate rather significant amounts of heat. It has been found that the performance and reliability of the components typically deteriorate as the temperature of the components increase. Computer systems are thus generally equipped with a mechanism (e.g., a fan) attached to a housing of the computer system to cool the components by cooling the interior space of the computer system. Although these types of mechanisms have been relatively effective in cooling the components of certain types of computer systems, they have been found to be relatively insufficient to cool the faster and more powerful components of today""s computers.
With the advent of faster and more powerful processors, the possibility that the processors will overheat has drastically increased. One solution to the overheating problem has been to directly cool the components themselves through the use of refrigeration systems. Refrigeration systems generally possess an evaporator positioned in thermal contact with a surface of the component to be cooled. Although refrigeration systems have been found to be relatively effective in maintaining the temperatures of individual computer components within acceptable ranges, it has been found that known refrigeration systems suffer from a variety of drawbacks and disadvantages when a computer system possesses a number of components (xe2x80x9cmulti-component systemxe2x80x9d).
For instance, one known technique of reducing the temperature of a multi-component system is to rely upon a single refrigeration system possessing a plurality of evaporators aligned in series along each of the components. That is, the evaporators are connected along a single refrigerant line such that refrigerant flows from one evaporator to the next. In this respect, the amount of refrigerant flowing into each of the evaporators is the same for each of the evaporators. Thus, known serially positioned evaporators do not allow for individual metering of refrigerant flow through each evaporator. As a consequence, evaporators positioned downstream from other evaporators may be adversely affected (e.g., downstream evaporators may receive superheated fluid which may actually cause a rise in their temperature). In addition, evaporators positioned relatively upstream and having lower power dissipation, may actually be cooler than the downstream evaporators.
An additional problem associated with known multi-load refrigeration systems arises from the fact that the flow rate through each of the evaporators is the same. In this respect, components producing a greater amount of heat will require a greater amount of refrigerant than components producing a relatively lesser amount of heat. This may cause the refrigerant to remain in liquid form as it enters the compressor. One possible effect of having liquid refrigerant enter into the compressor is that slugging may occur, which may ruin or otherwise damage the compressor.
Another manner of reducing the temperature of processors may include the provision of a separate refrigeration system for each component in a multi-component system. Although such a system may overcome some of the difficulties of serially positioned evaporators, the cost and space requirements involved with this type of system would be relatively substantial and thus may not be a viable technique for cooling the components.
According to the principles of the present invention, a refrigeration system is configured to allow for the mass flow rate of refrigerant flowing into the evaporators of a multi-load refrigeration system to be independently metered to thereby separately control the amount of heat dissipated by each of the evaporators, without suffering from the drawbacks and disadvantages associated with known refrigeration systems.
According to a preferred embodiment, the present invention relates to a refrigeration system for cooling a plurality of components in a computer system. The refrigeration system includes a compressor for controlling the flow of refrigerant through a refrigerant line and a plurality of evaporators configured to receive the refrigerant flowing from the compressor. The evaporators are configured for thermal attachment to the plurality of components, and the flow of the refrigerant into each of the evaporators is independently metered.
Additionally, the present invention pertains to a method for cooling multiple components of a computer system having multiple fluctuating heat loads. According to the method, a flow of refrigerant through a refrigeration system having a variable speed compressor is controlled. The refrigeration system includes a plurality of evaporators and a plurality of valves, each valve being configured to control the flow of the refrigerant through a respective evaporator. A saturation temperature of the refrigerant is sensed and the speed of a compressor is modified in response to the saturation temperature being outside a predetermined saturation temperature range.
In accordance with another preferred embodiment, the present invention relates to a method for cooling multiple components of a computer system having multiple fluctuating heat loads. According to the method, a flow of refrigerant through a refrigerant line in a refrigeration system having a constant speed compressor is controlled. The refrigeration system further includes a plurality of evaporators and a plurality of valves, each of the valves is configured to meter the flow of the refrigerant through a respective evaporator. A superheat temperature of the refrigerant flowing through each of said evaporators is checked. Each of the respective valves for the evaporators in which the evaporator superheat temperature is less than an evaporator superheat temperature set point is manipulated to decrease the flow of refrigerant therethrough. A processor temperature is sensed for those evaporators in which the evaporator superheat temperature exceeds or is equal to the evaporator superheat temperature set point.